A child being unintentionally left in a vehicle is an all too common occurrence—often with tragic results. Busy, forgetful, or traffic-stressed parents, day care workers, or other adults may simply forget a child is strapped into a child safety seat, or buckled into a vehicle seat, in an automobile or on a bus. Children often fall asleep in the seats, and are unable to alert the adult to their presence. Additionally, animals may sleep in the floorboard area, and an adult may forget and leave them trapped in the vehicle. A child or animal locked into an automobile, van, or bus on a hot day can die within hours.
One test monitored the interior temperature rise in two parked cars—a dark sedan with the windows closed and a light minivan with the windows open approximately 1.5 inches—on an afternoon with an ambient exterior air temperature of 93° F. Within 20 minutes, temperature readings in both cars exceeded 125° F. and reached approximately 140° F. in 40 minutes—a temperature rise of over 45° F. As this test shows, contrary to popular belief, “cracking” the vehicle windows in an attempt to allow ventilation while deterring entry from outside, is ineffective in protecting children or animals in the vehicle from the danger of heat stroke (Gibbs, et al., Heat Exposure in an Enclosed Automobile, Journal of the Louisiana State Medical Society. Volume 147 (12) 1995).
A variety of child safety seat occupancy sensors and alarms, designed to alert drivers to the presence of children in a vehicle, are known in the art. U.S. Pat. No. 6,909,365 discloses an alarm system comprising a switch operative to detect a child occupying a child safety seat, a sensor that detects when the ignition key of the vehicle is in an off position, and an alarm that triggers if the child seat is occupied when the ignition is turned off. U.S. Pat. No. 6,870,472 discloses a sensor for detecting when a child safety seat is occupied; a light sensor detects the state of the vehicle's dome light, indicating an open door. If a door is opened while the seat is occupied, an alarm sounds. U.S. Pat. No. 6,812,844 detects occupancy of the child safety seat by detecting whether the retention strap buckle is engaged, and discloses an air pressure transducer to detect when a door is opened.
These prior art child seat occupancy detection and alarm systems are deficient in several respects. The systems that detect occupancy of a child safety seat must generally be designed into the seat, and installed at the time of manufacture. While this may address the problem in the future, millions of child safety seats that lack such detectors are in use daily, potentially putting children at risk of being inadvertently left in a vehicle. Furthermore, even if a means is devised to upgrade existing child safety seats to include occupancy sensors, such sensors must be installed in every safety seat in which any child may ride. For a family with two or three infants or small children, or a child care facility that owns a plurality of safety seats, this multiplies the cost by each additional safety seat that must be upgraded.
Most of the prior art alarm systems additionally require some modification to the automobile, such as to detect whether a door is opened, the state of the ignition switch, or the like. Again, such sensors are either not designed into vehicles, or the outputs of sensors that are designed in are not readily available; hence existing vehicles must undergo potentially expensive modifications to accommodate the prior art alarms. In addition, once the modifications are performed, the alarm is only operative in the vehicle to which the modifications were made. Many families, child care centers, schools, churches, and the like may transport children in numerous vehicles.
Thus, a need exists in the art for a portable, self-contained system that is effective to alert, or remind, adults to the presence of passengers, including infants, children, and animals, upon exiting a vehicle. Such an alarm should be fully functional when placed in any vehicle, requiring no modification to either the child safety seat or the vehicle. Furthermore, a single alarm would ideally remind the adult of the presence of any child in the automobile, regardless of the number of child safety seats or which ones are occupied. In addition, it would be advantageous to utilize the alarm to remind the adult of other cargo, for example, perishable groceries that must be unloaded from the trunk, upon exiting the vehicle.